In general, an apparatus of such a type is known as an output apparatus that prints image data such as a face picture onto a recording medium such as a plastic card. For example, a large volume printing system is not suitable for printing of a certification card such as a driver's license, a membership card, or an ID card due to its inclusion of personal information.
Thus, recently, a multi-purpose printing system integrated into a computer network and configured to simultaneously perform printing of a face picture and its accompanying text and recording of electronic data such as personal information is used as on-demand printing. As a printing system, sublimation ribbon transfer, wax ribbon transfer, inkjet printing, electrostatic printing, and the like are used.
Among various printing methods as above, an intermediate transfer printing method is used when irregularities are formed on a surface of the recording medium and when a hologram or the like is coated on the recording medium surface. The intermediate transfer printing method is known as a method that forms a primary image on an intermediate transfer film (hereinafter, referred to as “transfer film”) and then transfers the primary image formed on the transfer film onto the recording medium by means of a downstream side platen and is used for a medium having irregularities on a surface thereof, a medium requiring surface coating, and the like.
Such an intermediate transfer printing apparatus is disclosed in, for example, Patent Document 1. An image is formed on a transfer film at a primary transfer (printing) position, and the transfer film is fed to a downstream side transfer platen. At the same time, a recording medium such as a card is fed to the transfer platen, and the image on the transfer film is transferred onto the recording medium by means of the transfer platen (while heat is applied by a heating roller).
In the apparatus of Patent Document 1, the transfer film is fed from a supply roll (supply spool) to a winding roll (winding spool). A printing platen for primary transfer and a transfer platen for secondary transfer are provided between the supply spool and winding spool. A feeding direction of the transfer film and a feeding direction of the recording medium are set in the same direction.
Thus, the transfer film delivered from the supply roll is subjected to image formation by means of the printing platen, and the image formed on the transfer film is transferred onto the recording medium such as a card by means of the transfer platen provided on the downstream side of the printing platen. As described above, the transfer film is fed in one direction, and the supply roll, printing platen, transfer platen, and winding roll are arranged in this order along the film feeding direction.
A heating roller is disposed opposite to the transfer platen. The heating roller holds the transfer film and recording medium between itself and transfer platen, brings them into pressure contact with each other, and applies heating thereto to thereby transfer the image on the transfer film onto the recording medium. The heating roller is configured to be movable between an operating position at which it is brought into pressure contact with the transfer platen and a retreating position at which it is positioned spaced apart from the operating position and is provided with a shifting unit such as a cam.
Such a feeding method has a problem in that the intermediate transfer film is consumed more than necessary due to a variation in position of a card rear end (print terminating end). That is, the heating roller cannot (almost impossible) be separated from the card simultaneously with the termination of printing on the card rear end due to length error of the card and card feeding precision error, so that a print terminating portion of the transfer film is brought into contact with the heating roller to be consumed.
More specifically, in this feeding method, a contact surface with the heating roller is generated at its rear end portion of the intermediate transfer film due to the variation in position of the card rear end (print terminating end). The film surface that has contacted the heating roller cannot be used any more. That is, an unnecessary heated portion is generated every time printing is performed at the print terminating end portion, and the print terminating end portion is inevitably consumed.
Patent Document 2 proposes a film feeding method in which a feeding direction of the transfer film and a feeding direction of the card are set in opposite directions so as to eliminate the above-described waste of the transfer film. More specifically, in method of the Patent Document 2, the transfer film is delivered from the supply roll, through the transfer platen, to the downstream side printing platen, where the transfer film is subjected to image formation and, thereafter, the resultant transfer film is switched back (back-fed) to be fed in the same direction as the card feeding direction to the transfer platen.
According to the feeding method of Patent Document 2, the waste of the transfer film can be eliminated. That is, the rear end portion of the film onto which the image has been transferred by means of the transfer platen is followed by a spent film, surface, thus preventing a surplus heated portion from being generated by the heating roller.